Current intrusion detection systems use fiber optical cables with added sensing devices along the length of the cable. The fiber cables are usually greater than a half inch in diameter, have significant strength members/coatings, and often include electrical power wires. These suspended optical fibers usually weigh more that 10 pounds per mile and can be quite expensive due to their significant construction. Further, the deployment of suspended optical fibers requires special fiber-optic-laying ships with high specialized, and very expensive, services. Finally, to transform the suspended optical fiber into an intrusion sensor requires dedicated sensing devices to be inserted/connected along the length of the cable and/or at end points of the cable. These dedicated, expensive, and discrete sensor can monitor acoustic disturbances over long distances (distances greater than 25 miles), such as along a pipeline or trans-oceanic distances along the sea floor between two landmasses, with a first suspended optical fiber connected to a remote sensing unit. The remote sensing unit receives an optical return signal, created by the acoustic disturbance, and generates a representative signal having features of the optical return signal. The representative signal is transmitted to an analysis engine for monitoring. Further, the suspended optical fiber requires a plurality of regenerators to prevent signal loss over long distances, as disclosed in U.S. Pat. No. 8,937,713. Alternatively, intrusion detection systems using fiber optical cables can monitor a disturbance (e.g. acoustic pressure, mechanical pressure, or thermal strain) over distances greater than 3 miles, in which a single mode or multimode suspended optical fiber is connected to a time-domain reflectometer. The suspended optical fiber is deformed by the disturbance at a plurality of locations, thereby creating optical return signals relative to the locations at which the disturbance occurred, as disclosed in U.S. Pat. No. 7,274,441.